Electromagnetic switching means



Nov. 7, 1950 L. M. PERSONS ELECTROMAGNETIC SWITCHING MEANS 2 Sheets-Sheet 1 Filed Aug. 21, 1946 INVENTORI LAWRENCE M. PERSONS BYYaa;

r ATTORNEYS.

Nov. 7, 19 50 L. M. PERSONS 2,528,777

ELECTROMAGNETIC SWITCHING MEANS Filed Aug 21, 1946 2 Sheets-Sheet 2 FIG. 3

FIG. 4

INVENTOR LAWRENCE M. PERSONS ATTORNEYS Patented Nov. 7, 1950 UNITED STATES OFFICE ELECTROMAGNETIC SWITCHING MEANS Lawrence M. Persons, Chesterfield, Mo.,'assignor to McQuay-Norris Manufacturing Company, St. Louis, Mo, a corporation of Delaware Application August 21, 1946, Serial No. 692,103

Claims. 1

This. invention relates generally to electrical control apparatusand particularly to a relay and control circuit therefor which may be utilized on vibrating installations without chattering of the relay contacts. In electromagnetically operated relays of the character heretofore employed, it has been customary to construct the relay as lightly as possible in order thereby to render. it more highly sensitive to actuation by an appropriately arranged solenoid, Such lightness of construction, however, as was consistent with high sensitivity renders the relay susceptible to chattering of contacts when installed upon a body subject to vibrations. The chattering of the contacts may be suflicient to make and break the circuits controlled by the rela when it is desired to maintain such. circuit continuously energized, and in other cases where the chattering is insuilicient to make and break the control circuit the chattering nonetheless results in arcing at the contacts, and consequentl short life thereof.

vThe object of the invention, generally stated, is to provide a relay which, while sensitive to electromagnetic impulses, is nonetheless not subject to chattering upon vibration.

A further object of the invention is to provide a control circuit utilizing a relay of the character referred to, wherein and whereby an actuating solenoid for the relay will continue to be energized until the contacts of the relay are moved beyond possibility of spontaneous return to their contact making positions.

; Another object of the invention is to provide a relay and rela 'circuit capable of being included in one leg of a control circuit without necessitating a hot wire to excite the relay.

1 Other objects will become apparent to those skilled in the art when the following description is read in connection with the accompanying drawings, in which Figure l is a sectional view of a'relay constructed in accordance with the present invention.

' Figure 2 is a plan view of the relay shown in Figure 1, showing the line ll along which the sectional view of Figure l is taken.

Figure 3 is a wiring diagram of a control circuit utilizing the relay of the present invention.

And Figure 4 is a wiring diagram of another control circuit utilizing the relay of the present invention.

In accordance with the present invention, an electromagnetically actuated relay is provided with a movable contact member so arranged that it is spring biased into every contact making position, and so organized that a movable contact member remains in contact making position despite the fact that the electromagnetically actuated operating means may become deenergized.

f- The invention is further characterized b the feature that the-electromagnetic actuator is so coordinated with the movable contact member that the electromagnet does not become deenergized (by virtue of a contact being broken thereby) until the movable contact member has been so fa'r'm'ov-ed out of its contact making position that it will not spontaneously return to that position.

' The invention further contemplates that'the contacts being controlled b any given solenoid in a relay be so arranged in circuit as to interrupt the flow of power, not only to the solenoid itself, but to an electrical apparatus which is being controlled Referring now to Figures 1 and 2'of the drawlugs for an illustrative embodiment of the relay of this invention, a pair of solenoids, l and 2, are mounted upon a base 3, and provided with an-exte'rior magnetic path of any suitable type. Arranged axially vithin the solenoids i and 2 is a stationary core piece 4, and an axiall movable core piece 5, which when the solenoid is de'energized comes to'rest in the position shown in full lines within'the solenoid 2 in Figure l, but when the solenoidi's energized assumes the position indicated' within solenoid I in Figure 1. The movable core piece 5 has a non-magnetic stem 6 extending axially therefrom through stationary core piece 4, and projecting substantially above base 3 The solenoid i is-constructed identically to the solenoid-- 2-, and has a non-magnetic stem 6E3, corresponding to-the stem 6 for solenoid 2.

Pivotally mounted upon the shaft 7, whose op.- posite ends are carried'by end plates 8, on base 3, is a movable contact member 9, carrying at its opposite ends, in electrically insulated relation one from the ther, movable contacts l9 and H, eachof which, it will be apparent from Figure 2, constitutes-a conductor for bridging a pair of stationary contacts, |2l3 in the case of contact l0, and I l-15in the caseof contact H. The stationary contacts [2, I3, l4 and I5 are suitably mounted upon aninsulation plate it, carried by end-platest'."

As shownin dotted lines in Figure 2, the movable contact member 9 has a central opening 11', within which is accommodated a lever l8, also pivoted upon shaft lgbut adapted to be moved relative to the movable contact member 9. Interconnecting the lever l8 and movable contact member 9 isa pair of coiled springs it2il, which are respectively engaged overa tongue 2! and-22 on the extremitiesof-the lever 18. The other ends of the springs [Hand 20 are respectively engaged over tongues 23 and 24 at the extremities of the opening i7, withinmovable contact member 9.

Lever I8- is so disposed as to be engaged by stem 6, of solenoid 2 at 25 upon energization of solenoid '2. Likewise, stem 60 of solenoid I is engageable with lever 18 at 26.

It will-be observed that if the solenoid l been= ergized, stem-= 60 will strike lever-l8, and move the same in a clockwise direction without, during the initial phases of the movement, affecting the position of movable contact member 9. Such rotation of lever I6 is, however, resisted by springs I9 and 29, until the clockwise movement of lever |8 brings the lever into alignment with the contact member, whereupon the slightest further movement of the lever I8 in the clockwise direction is assisted by springs I9 and a,

influence of solenoids I and 2, respectively, is so coordinated with the arrangement of lever and movable contact member 9, that the stem 6 and 69 do not reach the limit of their travel until after lever I8 has been moved thereby substantially beyond the position whereat it is in alignment with movable contact member 9, which is to say beyond the position whereat the efforts of springs I9 and 20 cease to resist relative movement between the parts and begin to assist such relative movement.

It will be apparent from the structure just described that once either of the solenoids and 2 has been energized for a time sufiicient to cause any movement of the movable contact member 9, such movement of the movable contact member will continue to the opposite limit regardless of whether the solenoid which initiated such movement continues to be energized or not. It is also apparent that after such movement has been accomplished the movable contact member will remain in its newly assumed position despite the fact that the solenoid which initiated such movement may be deenergized.

Referring now to Fig. 3, for an illustrative control circuit utilizing the present invention, any suitable source of power may be connected through leads 30 and 3|, so as to selectively energize either of two loads, 32 and 33, which latter may be any electrical apparatus. Lead 30 is connected to stationary contacts I3 and I4 at opposite ends of the relay above described. When the relay is in the position shown, movable contact member bridges stationary contacts I4 and I5 and completes a circuit through load 33 directly to lead 3|. The closure of contacts |4-|5 also completes a circuit through solenoid 2 to contact 34, of a pilot switch consisting of a lever 35 pivoted at 36 and biased in a counterclockwise direction by spring 31, but provided with an actuating member 38, which is under the influence of an instrument such as a thermostat orpressure instrument. Lever 35 is a conductor which interconnects contact and 4| at opposite ends thereof with a conductor 39 extending to lead 3| of the power circuit. It will be observed, therefore, that contacts I4 and I5 are not only in series with the load 33, but are in series with solenoid 2. Consequently, neither the solenoid 2, nor the load 33 can be energized when movable contact II is separated from stationary contacts I4 and I5.

The opposite side of the circuit shown in Figure 3, and concerning load 32 and solenoid I, is identical to the arrangement just described.

,With the parts of the relay the position 4 shown in Figure 3, if the member 38 be actuated, so as to cause lever 35 to rotate in a counterclockwise direction, and make contact between movable part 40 and stationary 34, it is apparent that solenoid 2 will become energized by becoming in parallel circuit relation with load 33. Such energization of solenoid 2 will effect an upward movement of plunger 6, and cause a counterclockwise rotation of lever I8 of the relay, with resultant compression of springs I9 and 20 during the initial stages of such rotation, and until lever l8 has aligned itself with movable contact member 9, whereupon springs I9 and 20 will reverse their action and tend to assist the relative movement between lever I8 and movable contact member 9, resulting in a separation of movable contact II from stationary contacts I and I5. Separation cannot occur, however, until after solenoid 2 has been energized for a period sufiicient to move stem 6 to an extent such that lever I8 is rotated beyond the point whereat springs I9 and 29 exert their tension to separate movable contact II from stationary contacts I4 and I 5 and maintain such separation. Upon the separation of movable contact II from stationary contacts I4 and I5, solenoid 2, as well as load 33, is immediately deenergized, but this does not effect the position of movable contact member 9, which maintains its new position under the influence of springs I9 and 20.

If thereafter the actuating member 38 operates to close the pilot switch circuit between movable contact 4| and stationary contact 42, solenoid I is energized to move stem 60 upwardly in the manner just described in connection with the operation of solenoid 2, but with the reverse effect upon the movable contact carrier 9.

Referring now to Figure 4 for a further example of the application of the relay to a control circuit in which the actuating solenoid is connected in gization, not only of the solenoid itself, but of the load, a pair of leads 5| and 52 from any suitable series with a set of contacts which controls enersource now provided. Lead 5| extends directly to a motor 53', or other suitable electrical appliance and therebeyond is connected to stationary contact I l. From stationary contact I4, a lead 55 extends to solenoid I, of the relay and thence to a yieldable switch member 55, mounted at 56, and having a contact 51 at the end thereof. 7

From stationary contact l5, a lead 59 extends to a yieldable switch member 59, mounted at 69 and having a contact 6| at the free end thereof. From mounting 60, a lead 62 extends to solenoid 2, and therefrom, via lead 63, connection is made to lead 52 of the power circuit. Lead 52 of the power circuit is also directly connected to a yieldable switch member 64, mounted at 65, having a contact 66 at the free end thereof. Any suitable temperature or pressure actuating means, such as 61, may be provided for moving contact 66 into engagement with contact 6| and the latter then into engagement with contact 5'! under predetermined conditions. Each of the yieldable switch members 55, 59 and 64 may be a leaf spring or spring biased, so that when the contacts 51, 6| and 66 are in engagement, the springs are under tension, and vibration of the installation will not cause chattering of the contacts due'to the spring tension they are under. Moreover, such a device lends itself to connection in a circuit, as hereinafter described, so that no current path is completed until all three contacts engage,

yet, once engaged, the circuit is not broken With the apparatus in the position shown in Figure 4, the circuit through solenoid l and motor 53 is dead by virtue of the separation of contact 51 from contact 6 l while the circuit through solenoid 2 is dead by virtue of the separation of movable contact H from stationary contacts 14 and 15. If now the actuator 61 be raised, so as to efiect engagement between contacts 6| and 66, the action is to effect a short circuit across solenoid 2, but due to the separation at contacts I4 and I5, the circuit is not completed through motor '53. Further movement of the actuator 61, however, brings contact 6| into engagement with contact 51, and a circuit is thereby completed through solenoid 5, lead 54 directly to and in series with motor 53, so that solenoid l is energized by the power current for motor 53. Such energization of solenoid I lifts stem 80 to move lever I8, as described hereinbefore, and causes movable contact member 9 to assume the opposite position from that shown, thereby closing the circuit between contacts M and I5 and short circuiting solenoid i through lead 58.

If now the actuating member 61 recedes from its previous position, the breaking of contact between contacts 5? and 61 does not affect the maintenance of the circuits previously established. Consequently, as pressure is released between contacts 51 and SI, the former may vibrate without making and breaking any live circuit, but if such recession of the actuator 61 continues to the point where contact 6| becomes separated from contact 66, a circuit is established through lead 62 to solenoid 2, and thence through lead 63, so that solenoid 2 now becomes energized by the power current to motor 53, with resultant movement of stem 6 to cause a breaking of the circuit at contacts |4I5. Once this is accomplished, switch members 64 and 59 may vibrate freely without making and breaking any live circuit.

From the foregoing description, those skilled in the art will readily understand that the invention accomplishes its objects and provides a relay and a relay circuit which is adaptable to vibrating installations without likelihood of chattering of energized contacts due to the vibration of the installation. While one complete embodiment of the relay has been described in detail,

and a full disclosure has been made of two illustrative control circuits, it is apparent that the invention is not limited to the details of the foregoing disclosure, but to many modifications, variations and applications thereof which will present themselves to those skilled in the art, without departing from the spirit or the invention, or the scope of the appended claims.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

1. A control circuit for electrical apparatus, comprising, a two coil relay having a movable contact for bridging a pair of stationary contacts, one of said coils when energized actuating said movable contact into and the other out of engagement with said stationary contacts, a lead extending from one of said stationary contacts to said apparatus, a lead extending from source to the other stationary contact, one coil of the relay being permanently connected in series in said last named lead, and a switch arranged when closed to short circuit said relay coil, said switch controlling the energization of the second relay coil.

2. A control circuit for electrical apparatus, comprising, a two coil relay having a movable contact for bridging a pair of stationary contacts, one of said coils when energized actuating said movable contact into and the other out of engagement with said stationary contacts a lead extending from one of said stationary contacts to said apparatus, a lead extending from source to the other stationary contact, the last mentioned coil of the relay being permanently connected in series in said last named lead, and the first mentioned coil of said relay being in series in a controllable circuit between the source and the first mentioned stationary contact, and switching means in said controllable circuit for short circuiting the first mentioned relay coil when the last mentioned relay coil is connected to source.

3. A control circuit for electrical apparatus, comprising, a relay having a pair of coils operating respectively to move contact members toward and away from circuit making position, supply lines, and a control switch arranged in circuit so that when closed one relay coil is connected across the supply lines and the other coil is short circuited; said other relay coil being permanently connected in series circuit relation between one supply line and one contact member but energized only when said control switch is open.

4. A control circuit for electrical apparatus, comprising, a relay having a pair of coils operating respectively to move a contact member toward and away from circuit making position in a main circuit, a control switch having three contacts arranged for progressive engagement first between two and then among all, two of said contacts being connected in one leg of said main circuit, one of said relay coils being permanently connected across two control contacts to be short circuited thereby when said two control contacts engage, and the other relay coil being connected between the third control contact and the other leg of said main circuit to be energized when said third control contact is engaged.

5. A control circuit for electrical apparatus, comprising, a relay having a pair of coils operating respectively to move contact members toward and away from circuit making position, supply lines, and a control switch arranged in circuit between one of said supply lines and one of said coils, said switch being movable into and out of a position whereat the circuit to said one coil is made, and said switch having auxiliary contacts engageable to short circuit the other coil when the circuit is made to the first coil.

LAWRENCE M. PERSONS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Certificate of Correction Patent No. 2,528,777 November 7 1950 LAWRENCE M. PERSONS It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 4, line 43, strike out series With a set of contacts which controls enerand lnsert the same after the Word 1n second occurrence, line 40, same column; column 6, line 40, before two insert said;

and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Office. Signed and sealed this 16th day of January, A. D. 1951.

THOMAS F. MURPHY,

Assistant Oommz'ssz'oner of Patents.

Certificate of Correction Patent No. 2,528,777 November 7, 1950 LAWRENCE M. PERSONS It is hereby certified that error appears in the printed specification of the above numbered patent requirmg correction as follows:

Column 4, line 43, strike out series With a set of contacts which controls enerand msert the same after the Word in second occurrence, line 40, same column; column 6, lme 40, before two lnsert said;

and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Office. Signed and sealed this 16th day of January, A. D. 1951.

THOMAS F. MURPHY,

Assistant Commissioner of Patents. 

